Abstract:

【Objective】 The objectives of the present study were to search for genetic markers associated with high litter size and to provide a scientific basis for marker-assisted selection for high proliferation in goats. 【Method】 Fifteen pairs of primers were designed to detect single nucleotide polymorphisms of exon 1 to exon 9 of progesterone receptor (PGR) gene in Jining Grey, Boer, Liaoning Cashmere and Angora goats by PCR-SSCP. 【Result】 Only the products amplified by primers P1, P8 and P9 displayed polymorphisms. For primer P1, three genotypes (AA, AB and BB) were detected in Jining Grey goats, two genotypes (AA and AB) in other goat breeds. Sequencing revealed one mutation (31G→A) of PGR gene in the genotype BB in comparison to the genotype AA, and this mutation resulted in an amino acid change of Ala→Thr. The does with genotype BB had 0.52 (P＜0.05) or 0.98 (P＜0.001) kids more than those with genotype AB or AA, and the does with genotype AB had 0.46 (P＜0.05) kids more than those with genotype AA in Jining Grey goats. For primer P8, only one genotype (CC) was detected in Jining Grey goats, two genotypes (CC and CD) were detected in Boer goats, and three genotypes (CC, CD and DD) were detected in other goat breeds. Sequencing revealed one mutation (2810C→G) of PGR gene in the genotype DD in comparison to the genotype CC, and this mutation did not cause any amino acid change. For primer P9, two genotypes (FF and FG) were detected in Jining Grey and Boer goats, and three genotypes (FF, FG and GG) were detected in other goat breeds. Sequencing revealed one mutation (60128T→A) of PGR gene in the genotype GG in comparison to the genotype FF, and this mutation did not cause any amino acid change. The does with genotype FF had 0.32 (P＞0.05) kids more than those with genotype FG in Jining Grey goats. 【Conclusion】 These results preliminarily indicated that the PGR gene is either a major gene that influences the prolificacy in Jining Grey goats or a molecular marker in close linkage with such a gene.

Key words: goat, prolificacy, progesterone receptor gene, PCR-SSCP